scholarly journals Quality of pejerrey (Odontesthes bonariensis) eggs and larvae in captivity throughout spawning season

2014 ◽  
Vol 12 (3) ◽  
pp. 629-634 ◽  
Author(s):  
Tomás Chalde ◽  
Mariano Elisio ◽  
Leandro A. Miranda

The aim of this work was to assess the quality of pejerrey eggs and larvae throughout its spawning season. Fertilized eggs were taken on September, October, November, and December from a captive broodstock. The egg diameter, yolk diameter, and oil droplets area decreased along the spawning season, with higher values in September. Fertilization and hatching rates decreased throughout this period, with highest values in September (88.0%; 55.2%) and the lowest values on December (43.0%; 25.2%). The larvae hatched from eggs obtained on October were the heaviest and longest (1.57 mg; 8.24 mm). The survival rate at 30 days post hatching (dph) was similar in larvae from September and October eggs (66.1%; 62.9%) with a sharp decrease in larvae from November and December eggs (22.4%; 23.3%). Furthermore, the highest body weight (15.1 mg) and total length (15.25 mm) at 30 dph were obtained in larvae from October eggs. The results obtained showed that overall eggs quality was better at the beginning of the spawning period, influencing the larvae performance.

1998 ◽  
Vol 76 (3) ◽  
pp. 588-592 ◽  
Author(s):  
Margaret PM Burton ◽  
Shawn R Flynn

Male and female capelin (Mallotus villosus Müller) were captured in 1993 at the start of spawning and males were captured in 1995 at the end of the spawning period. All male fish from both years died within 6 weeks of capture. Spent males captured in the wild showed almost empty testes with very few residual sperm and no evidence of developing spermatocytes. All female fish survived the first 6 weeks and over 50% survived 20 weeks. Sampling of the surviving females after 20 weeks showed evidence of prior spawning and progressive development of oocytes for the next summer's spawning season. It was concluded that while males may be semelparous, females are inherently iteroparous.


2016 ◽  
Vol 64 (3) ◽  
Author(s):  
Jorge Boza Abarca ◽  
Marvin Ramírez-Alvarado ◽  
Juan Barquero-Chanto ◽  
Emilia Calvo-Vargas ◽  
Karen Berrocal-Artavia

The croakers or drums are commercial species, which have been overfished in the Nicoya Gulf, Costa Rica. This study aimed to describe, for the first time, the reproduction and the ontogeny of weakfish, Cynoscion squamipinnis in captivity, in order to perform restocking and mariculture proyects. Wild fish (n= 6, 1-2 Kg) were captured and maintained in the Estación de Biología Marina Juan Bertoglia Richards (Puntarenas, Costa Rica) for a two years period (October 2006- December 2008). During this period, maturation stage was monitored periodically by cannula samples in the females (n= 3) and gentle massage in males (n= 3). All fish were stocked in an 18 t tank, with aeration, 33-35 ups of salinity, and a constant temperature (29 ± 1 °C). The spawning period occurred from January to March 2009, producing 162 000 eggs in three spontaneous spawns. The fertilization percentage was 50-60%, and survival after hatching was 60-85%. The egg diameter was 0.852 mm (Standard deviation (SD)= 0.039), and oil drop of 0.269 mm (SD= 0.016). In the embryonary development, the first mitotic division (MD) was observed one hour after spawning (has), the second MD was 1:30 has, the third MD was 2:00 has, the fourth MD was 2:30 has, and fifth MD at 3:00 has. Morule was observed 3:30 has, the blastule 4:30 has, the gastrule 8:30 has, C shape at 10:00 has, and C shape at 12:00 has. After 19 has hatching larvae occurred. The total length (TL) of the larvae was 2.234 mm (SD= 0.122), and the nothochordial length (NL) was 2.179 mm (SD= 0.119). Preflexion stage was observed 49 has, flexion stage was 11 days after spawn (das) (3.767 mm LT (SD= 0.209)), and postflexion stage was 14 das (4.015 mm LT (SD= 0.302)). After 45 das, the juvenile weights 3.68 g (SD= 1.09). Hatch time of the weakfish larvae was minor than of others croaker species. The stages times of embrionary development were a little different from others croaker species, and probably respond to genetic characteristics of each species and the eggs incubation temperature. The spontaneously spawning without broodstock hormonal applications, and the juveniles production in captivity showed that weakfish is a potential species for restocking programs and mariculture projects.


2020 ◽  
Vol 1 (4) ◽  
pp. 63-67
Author(s):  
N. N. Shumilina ◽  
◽  
E. E. Larina ◽  

The pride of Russia has always been sable. Sable is unique not only in the quality of its fur, but also in the fact that almost the entire range of its habitat is located on the territory of our country. It was in our country that this animal was first bred in captivity. In this regard, Russia has long had a monopoly on the production of sable skins. In 1969, the black sable breed was approved, and in 1998, the «Saltykov» type of sable was approved. JSC «Saltykovsky Breeding farm» has created a unique herd of dark Sables with evenly spaced gray hair, the skins of which are valued at auctions by 10–30% more expensive [2]. The article presents the results of a comparative assessment of the productive qualities of Sables without gray hair and with different degrees of gray created in JSC «Plemzverosovkhoz » Saltykovsky» livestock. As a result of the analysis, it was found that Sables with gray hair have higher bonitirovki scores (more than 50%). Analyzing the indicators of bonitirovki in males and females with different degrees of gray hair, it was found that the quality of pubescence and color of males with bright gray hair is significantly superior to individuals without gray hair, the same trend is observed in females. In addition, a positive correlation was found (0,79) between the weight of skins in grams, their length and area both in Sables without gray hair, and in individuals with different degrees of gray hair. The most common defect on skins without gray hair is soaking.


2018 ◽  
Vol 115 (44) ◽  
pp. 11215-11220 ◽  
Author(s):  
Dora L. Costa ◽  
Noelle Yetter ◽  
Heather DeSomer

We study whether paternal trauma is transmitted to the children of survivors of Confederate prisoner of war (POW) camps during the US Civil War (1861–1865) to affect their longevity at older ages, the mechanisms behind this transmission, and the reversibility of this transmission. We examine children born after the war who survived to age 45, comparing children whose fathers were non-POW veterans and ex-POWs imprisoned in very different camp conditions. We also compare children born before and after the war within the same family by paternal ex-POW status. The sons of ex-POWs imprisoned when camp conditions were at their worst were 1.11 times more likely to die than the sons of non-POWs and 1.09 times more likely to die than the sons of ex-POWs when camp conditions were better. Paternal ex-POW status had no impact on daughters. Among sons born in the fourth quarter, when maternal in utero nutrition was adequate, there was no impact of paternal ex-POW status. In contrast, among sons born in the second quarter, when maternal nutrition was inadequate, the sons of ex-POWs who experienced severe hardship were 1.2 times more likely to die than the sons of non-POWs and ex-POWs who fared better in captivity. Socioeconomic effects, family structure, father-specific survival traits, and maternal effects, including quality of paternal marriages, cannot explain our findings. While we cannot rule out fully psychological or cultural effects, our findings are most consistent with an epigenetic explanation.


Koedoe ◽  
2018 ◽  
Vol 60 (1) ◽  
Author(s):  
Bernard W.T. Coetzee ◽  
Sam M. Ferreira ◽  
Kristine Maciejewski

The global conservation status of Nile crocodiles (Crocodylus niloticus) was last assessed in 1996. The species presents particular difficulty in monitoring because it can be cryptic, require expertise to handle, and caudal tail tags and transmitters are often lost. Some studies advocate mark-recapture techniques based on photograph identification of the unique scute markings of crocodile tails as a non-invasive means of monitoring their populations. Researchers developed this method with crocodiles in captivity. In this study, we test the technique under field conditions by monitoring crocodiles from 2015 to 2017 in the Sunset Dam in the Kruger National Park. Using a Cormack-Jolly-Seber open population model, we found that the dam may host 15–30 individuals, but that there is a high turnover of individuals and much uncertainty in model outputs. The dam’s population thus has high rates of immigration and emigration. The method proved challenging under field conditions, as there was bias in identifying scute markings consistently. The efficient use of the method requires an exceptional quality of photographic equipment. Animal crypsis, however, remains an issue. In this study, we discuss how to improve the mark-recapture photography methodology, especially to adapt the technique for citizen science initiatives.Conservation implications: Using scute mark-recapture photography presents challenges under field conditions. These challenges require innovative, practical and analytical solutions to successfully use the technique before monitoring programmes, aimed at ensuring the persistence of crocodiles in the wild, can be implemented.


2013 ◽  
Vol 33 ◽  
pp. 63-68 ◽  
Author(s):  
L. A. Zapata ◽  
B. S. Beltrán-León ◽  
J. C. Herrera ◽  
P. Jiménez-Tello ◽  
L. M. Prieto ◽  
...  

Abstract. Commercial fishing of small pelagic species in Colombia, mainly "carduma" (Cetengraulis mysticetus) and "plumuda" (Opisthonema spp.), has been recorded since 1970. Both are used to produce fish meal for aquaculture and poultry and for canned foods. These two species are filter feeders, and therefore support higher levels of the food chain (other fish, birds and marine mammals), and artisanal fishermen use them as bait. Between 2005 and 2010, 86.131 t have been captured (X = 14.355 t yr−1), and a strong reduction was noticed in 2009 (6.969 t). Carduma is considered a total spawning species. However, from 1997 to 2000 and from 2008 to date, atypical reproductive behavior of the species has been observed, including partition of the spawning period and the reduction of the volume of eggs and larvae released to the environment. Both situations are linked to thermal anomalies such as El Niño and La Niña events. Therefore, the process of assigning the global quota of extraction has been revised to take into account the reduction of total capture during the last years and the inconsistencies of the reproductive processes. The Ministry of Agriculture reduced the quota by 10%, leaving available a total of 27 000 t for 2010 and reduced it again to 25 000 t for 2011. It is important to maintain the management measures that are already implemented on this resource (bans during reproduction seasons, catch quotas, regulation of mesh sizes for the fishing nets, and limiting the number of new vessels) and considering other measures such as season closure for recruitment and establishment of marine protected areas to further contribute to the sustainability of these fisheries.


A Total of 379 pen shells Atrinapectinata were collected from February 2017 to January 2018 in the coastal waters of Maqueda Bay. Measurement and analysis of length and weight were done using FiSAT software. Population parameters were assessed to evaluate the stock status which includes the asymptotic length (L∞) and growth coefficient (K) to be 34.65 cm, 0.77 year−1 respectively. Specimens of A. pectinata reached a mean length of 20.98 cm. Length-weight relationship resulted to “negative allometric” 0.0462L2.6533 R2 = 0.7823; signifying pen shells growth was faster in length than on weight. The recruitment pattern was continuous over the year with one major peak during rainy season (July). In addition, the highest catch based on collected sampling date catch was during summer, which suggest as the peak season of the species in the area. Furthermore, the average catch annually of hookah diver was 17.69208. Higher condition index was recorded from April to May, September and January, indicating the high quality of pen shell meat and is recommended as the best period to harvest pen shell whereas June to August and October to December can be concluded as the spawning period of the pen shell and the ideal period to institute close season. Further analysis revealed that the pen shell was nearly facing overexploitation with the exploitation rate (E = 0.46) mainly due to lack of a minimum limit size and also due to an increase in the harvesting effort. The estimated total mortality (Z), natural mortality (M) and fishing mortality (F); 1.36 year−1, 1.01year−1 and 0.62 year−1, respectively. Using the mentioned (Z), (M), (F) and (E), the total population resulted to 84725.7 suggesting that half of the population has been exploited due to overfishing


2012 ◽  
Vol 12 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Wilawan Khanitchaidecha ◽  
Futaba Kazama

To study the performance of an attached growth reactor on nitrate-nitrogen (NO3-N) removal by a hydrogenotrophic denitrification process, the reactor was operated under various H2 flow rates (30, 50 and 70 mL/min), hydraulic retention times (HRTs) (2.6, 3.1, 4.7 and 6.7 h) and inorganic carbon (IC) concentrations (excess and no IC addition). Synthetic NO3-N water was prepared in accordance with the groundwater quality of the study area: Chyasal in Kathmandu Valley, Nepal. The results show an increase in denitrification efficiency with H2 flow rate and HRT. Further, for effective denitrification, the dissolved hydrogen (DH) during operation should be maintained at greater than 0.1 mg/L. A sharp decrease in the denitrification efficiency from ∼96% (under excess IC) to 10–35% (under no IC) suggested occurrence of denitrification inside the attached growth reactor by a hydrogenotrophic process (using H2) as well as heterotrophic process (using internal organic carbon). The good performance of the attached growth reactor in terms of high efficiency, low H2 supply and short HRT requirement indicates the reactor's appropriateness for groundwater remediation through NO3-N removal.


2018 ◽  
Vol 97 (7) ◽  
pp. 2506-2515 ◽  
Author(s):  
J. Herrera ◽  
B. Saldaña ◽  
L. Cámara ◽  
J.D. Berrocoso ◽  
G.G. Mateos

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